Week 10: Disaster Risk and Vulnerability

• Natural disaster is a major adverse event resulting from natural processes of the Earth; examples include floods, hurricanes, tornadoes, volcanic eruptions, earthquakes, tsunamis, and other geologic processes.
• Natural disaster is an unusual (extreme) condition - a sudden environmental change.
• Although it is mainly caused by natural forces, it could be related to human activities.
  

• Greenhouse gas concentration increase -> Temperature rise
• Consequences of Climate Change
  • Short-term: increased intensity and frequency of extreme weather events
  • Long-term: temperature rise, sea level rise, land loss, ecological system change
• Impacts to Human
  • Natural Disasters
  • Shrinking natural resources and ecological services

• Prediction - predicting trends of climate and environmental changes
• Impact Assessment - quantifying impact of the changes to human society
• Uncertainty management and communication - deliver uncertainties of prediction and assessment to the public
• Mitigation - Designing strategies and plans to mitigate the impact

• Extreme event
• Disaster
• Risk
• Exposure
• Vulnerability
• Resilience

Risk = Extreme event * Exposure * Vulnerability

• The occurrence of a value of a weather or climate variable above (or below) a threshold value near the upper (or lower) ends ('tails') of the range of observed values of the variable.
• Quantified by frequency and intesnity
• Varies in space and time
• Examples:
  • Extreme drought, rainfall, wildfire, heat
  • FEMA 50/100-year-flood zone
  • Potential innundated area after sea level rise

Can be defined statistically

• To the presence (location) of people, livelihoods, environmental services and resources, infrastructure, or economic, social, or cultural assets in places that could be adversely affected by physical events.
• Intersection of human society and extreme event
• Examples:
  • Population/household in 100-year- zone
  • Urban area in low elevation coastal regions that could be innundated by sea level rise
  • Cropland in drought

• The propensity or predisposition to be adversely affected.
• It includes the characteristics of a person or group and their situation that influences their capacity to anticipate, cope with, resist, and recover from the adverse effects of physical events.
• Vulnerability is reflected from damage, loss, injury, lack of adaptive capacity or resilience.
• Example:
  • Heat wave hits the entire Honolulu. Some communities had more deaths or illnesses than others. We can infer these communities are more vulnerable to heat. Factors could be housing condition, higher percentage of elderly people, lower income and so on.

Resilience is defined as the ability of a system and its components to anticipate, absorb, accommodate, or recover from the effects of a hazardous event in a timely and efficient manner.
Resilience more reflect a dynamic process along the disaster cycle

• Disaster is severe alterations in the normal functioning of a community or a society due to hazardous physical events (usually extreme events).
• Related to extreme event, exposure and vulnerability - overlay in GIS
• Disaster risk is the likelyhood of disaster at a certain place over a specific time period.

Assuming the objectives (human community, cropland, infrastructure) does not move in space. In most cases, mitigation plans, vulnerability reduction, resilience building do not include migration.

Cutter, S. L., Barnes, L., Berry, M., Burton, C., Evans, E., Tate, E., & Webb, J. (2008). A place-based model for understanding community resilience to natural disasters. Global Environmental Change, 18(4), 598-606.

Overlay is the most powerful function of GIS for risk and vulnerability assessment

• Assessment of risk, exposure and vulnerability (Overlay)
• Support the development of mitigation strategy, evacuation plan, and sustainable planning
• Emergency response and management

Setting a threshold, all areas below the threshold will be innundated.

Overlay with population data to estimate impacted population - Exposure

FEMA flood zones (100-year-flood zone)

• Overlay urban area with 100-year-flood zones (raster calculator)
• Aggregating % urban area in flood zone in each county (zonal statistics as table)

• Change of % urban in flood zone between 2001 and 2010 (Field calculator)

• Hotspot detection (Local Moran's I)
• Significant clusters with increase or decrease of %urban area in flood zone

Zoom-in to interesting clusters

Estimate population in each urban pixel geographical weighted regression

Overlay with population - % of population in 100-year-flood zones

25.3 million (8.3%) of population in the contiguous U.S. are in flood zone Top 10 counties ranked by %population in FEMA flood zone

• Vulnerability consists of many socio-economic, health, demographic, environmental factors
• Usually measured using an index approach
• Aggregating variables in geograhpic units (e.g. counties)
• Most widely used is social Vulnerability Index (SoVI) (Cutter et al. 2003)

Cutter, S. L., Boruff, B. J., & Shirley, W. L. (2003). Social vulnerability to environmental hazards. Social Science Quarterly, 84(2), 242-261.

Supported by textual desrciption in literature
Determine the influencing direction of variables (negative or positive)

• Variable selection (reduce colinarity): 260 -> 42 variables
• Dimension reduction using principal component analysis (PCA): 42 variables -> 11 factors
• 11 factors were added together with equal weights

Cutter, S. L., Burton, C. G., & Emrich, C. T. (2010). Disaster Resilience Indicators for Benchmarking Baseline Conditions. Journal of Homeland Security and Emergency Management, 7(1), 14.

• 36 variables describe 5 subcomponents of resilience, including Social resilience, Economic resilience, Institutional resilience, Infrastracture resilience, Community capital
  

• Variables in each subcomponent were added together with equal weights
  

• Finally, the 5 subcomponents were added with equal weights.

Assignment

https://github.com/qiang-yi/GEOG489/blob/master/labs/lab5_sea_level_rise.docx

Due date: April 7